Apparatus for handling building material sheets and the like

ABSTRACT

Apparatus suspendible from a boom and the like for handling a stack of generally rigid sheet-like articles. The apparatus includes a rigid frame which is somewhat C-shaped as viewed from one of its sides, with the frame including a generally upright cradle having an open laterally facing side for receiving a stack of sheets with the latter on edge in the cradle. Power-operated lift forks pivoted to the base of the frame are swingable between a lowered position for picking up and depositing a stack and a raised position for placing a stack within the cradle. In the raised position, the forks substantially close off the open side of the cradle.

United States Patent [1 1 Nutter [54] APPARATUS FOR HANDLING BUILDING MATERIAL SHEETS AND THE LIKE [75] Inventor: Ralph E. Nutter, Boring, Oreg.

[73] Assignee: Cascade Corporation, Portland,

Oreg.

[22] Filed: Nov. 30, 1970 [21] Appl. N0.: 93,635

[52] US. Cl. ..294/67 AA, 294/67 B [51] Int. Cl ..B66c 1/00 [58] Field of Search..294/67 A, 67 AA, 67 AB, 67 B,

[56] References Cited UNITED STATES PATENTS 3,040,916 6/1962 Preston ..2l4/61 3,301,587 1/1967 Heikkinen ..294/67 AA 51 Jan.9, 1973 FOREIGN PATENTS OR APPLICATIONS 180,777 9/1966 U.S.S.R. ..294l67 Primary Examiner-Gerald M. Forlenza Assistant Examiner-Lawrence J. Oresky Attorney-Kolisch & Hartwell [57] ABSTRACT Apparatus suspendible from a boom and the like for handling a stack of generally rigid sheet-like articles. The apparatus includes a rigid frame which is somewhat C-shaped as viewed from one of its sides, with the frame including a generally upright cradle having an open laterally facing side for receiving a stack of sheets with the latter on edge in the cradle. Power-operated lift forks pivoted to the base of the frame are swingable between a lowered position for picking up and depositing a stack and a raised position for placing a stack within the cradle. In the raised position, the forks substantially close off the open side of the cradle.

2 Claims, 4 Drawing Figures APPARATUS FOR HANDLING BUILDING MATERIAL SHEETS AND THE LIKE BACKGROUND AND SUMMARY OF THE INVENTION This invention pertains to apparatus for handling a stack of generally rigid sheet-like articles, such as building material sheets. More particularly, it pertains to such apparatus which may be carried suspended from a boom and the like.

In recent years, the use of sheet-like building materials, such as sheets of plywood, plasterboard, etc., has become very popular in the construction industry. Such sheets typically are relatively large and heavy, and are somewhat difficult and inconvenient to handle. For example, both the wide spread of a sheet, and its weight, make it difficult to maneuver into the proper location in a building, particularly when it must be transported several stories above the ground. As a consequence, handling of such sheets can be a time-consuming and costly matter, and heretofore has been considered a problem.

A general object of the present invention, therefore, is to provide novel apparatus for handling (i.e., picking up, holding, transferring and depositing) sheets of the type generally indicated above, which apparatus greatly simplifies, and substantially reduces the costs of, a sheet-handling operation.

Another general object is to provide such apparatus which is designed to handle more than one sheet at a time-specifically, a bundle or stack of sheets-and which can readily orient such a stack for convenient insertion into a building through an open door, window, or other opening therein.

A further and related object of the invention is to provide apparatus of the type indicated which is extremely compact and highly maneuverable.

Thus, and according to a preferred embodiment of the invention, the proposed sheet-handling apparatus comprises a rigid frame, which when viewed from one of its sides, has a generally C-shaped configuration. The frame contemplated includes an elongated upright spine, and upper and lower arm structures joined to ,and projecting laterally from one side of the spine. The

spine and arm structures form the C-shape mentioned above, and define three sides of a laterally outwardly facing, open-sided cradle for receiving sheets.

Pivoted adjacent the lower arm structure in the frame is a lift fork structure including a pair of spacedapart forks which can be swung under power between lowered positions adapted to pick up and deposit a stack of sheets, and raised positions adapted to place and confine such a stack within the cradle in the frame. In the lowered positions of the forks, their tines extend generally horizontally outwardly from the frame in substantially the same direction as the lower arm structure. In the raised positions of the forks, their tines extend upwardly between the arm structures, in positions substantially paralleling and spaced from the spine in the frame. With the forks in such raised positions, the tines substantially completely close off the open side of the cradle in the frame.

DESCRIPTION OF THE DRAWINGS These and other objects and advantages attained by the invention will become more fully apparent as the description which follows is read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a simplified and fragmentary top perspective view illustrating a sheet-handling apparatus as contemplated herein in a condition inserting a stack .of sheets through an opening in an upper story of a build- FIG. 2 is an enlarged fragmentary side elevation illustrating the sheet-handling apparatus of FIG. I is greater detail, with certain parts in the apparatus shown in several different positions;

FIG. 3 is a fragmentary front view taken generally along the line 3-3 in FIG. 2; and

FIG. 4 is a fragmentary view, on a larger scale than the other figures, illustrating details of means mounting the sheet-handling apparatus on the outer end of an extensible boom.

DETAILED DESCRIPTION OF THE INVENTION Turning now to the drawings, and referring first to FIG. 1, indicated generally at 10 is a sheet-handling apparatus as contemplated herein. Apparatus 10 is suspended from the outer end of an extensible and swingable boom 12 through a rotator l4 and a dual-axis pivot assembly 16. Boom 12 may be conventional in construction, and may be mounted, for example, on the frame of a suitable vehicle, such as a truck. As will be more fully explained, rotator l4 and pivot assembly 16 accommodate multidirectional maneuvering of apparatus 10.

In FIG. 1, apparatus 10 is shown in a condition confining and holding on edge a stack of sheets 18, which might typically be sheets of a building material such as plywood or plasterboard. In addition, the sheet-handling apparatus is shown in a condition being inserted by boom 12 through an opening (indicated in dashed outline at 19) in an above-ground story of a building, to place stack 18 in the building.

Considering details of apparatus 10, and referring to FIGS. 2 and 3, the apparatus includes a frame'22, and a swingable lift fork structure, or lift means, 24. Frame 22 is rigid, and is formed from welded-together sections of hollow, rectangular-cross-section tubingpreferably steel. The frame includes what is referred to herein as an upright spine 26, joined to which are upper and lower laterally outwardly projecting arm structures 28, 30, respectively.

Spine 26 includes a generally vertically disposed upper member 32, a pair of diverging intermediate members 33 joined to the base of member 32, and a pair of substantially parallel and vertically disposed lower members 34 joined to the bases of members 33. Extending between and interconnecting lower members 34 is a cross member 35. As can be seen in FIG. 2, members 32, 33, 34, 35 occupy a substantially common upright plane.

Upper arm structure 28 comprises a single tube member 36 joined to the top of spine member 32. Members 36, 32 are disposed at an angle slightly greater than relative to one another. Lower arm structure 30 comprises a pair of spaced-apart, substantially parallel tube members 38 which are joined to the bases of spine members 34. Members 38 are disposed substantially at right angles to members 34.

With frame 22 viewed from the side thereof illustrated in FIG. 2, it will be noted that it has a somewhat C-shaped configuration. The spine and arm structures in the frame form this configuration, and define an open-sided laterally outwardly facing cradle 40 in the frame.

Lift fork structure 24 is, in many ways, conventional in construction. It includes a pair of substantially parallel spaced-apart lift forks 44 whose tines 44a join at right angles with elongated mounting portions 44b. Forks 44 are suitably mounted on a frame 45 which includes a pair of parallel spaced-apart members 46 that extend between the mounting portions of the forks, and a pair of members, such as member 48, which join members 46.

Joined, as by welding, to the back sides of members 46 are laterally spaced pairs of brackets 50. Brackets S straddle pairs of brackets 52 which are joined to the outer ends of arm members 38. Pivot pins 54 pivotally interconnect brackets 50, 52, and accommodate swinging of the lift fork structure about a generally horizontal axis 55 which is substantially normal to the plane of FIG. 2. In particular, the lift fork structure is permitted to swing relative to frame 22 between a lowered position, shown partially in solid outline in FIG. 2, and a raised position, shown partially at 243 in dash-doubledot outline in FIG. 2. It will be noted that the lift fork structure in its lowered position, the tines of forks 44 extend laterally outwardly and away from the frame, in substantially the same direction as arm members 38. With the lift fork structure in its raised position, the forks tines extend upwardly between the arm structures in the frame, substantially completely closing off the open side of cradle 40, and generally paralleling the upright plane of spine 26.

According to the invention, the lift fork structure is swung under power, such being accomplished in the embodiment being described by a fluid-operated ram 56. The butt end of the cylinder in the ram is pivoted at 58 to brackets 60 which are joined to frame member 35 substantially centrally between opposite ends of this member. The outer end of the rod in the ram is pivoted at 62 to brackets 64 which are joined centrally to the back sides of members 46. With extension of ram 56, the lift fork structure swings toward its lowered position; and with contraction of the ram, the reverse takes place. With the lift fork structure in its lowered position, ram 56 is disposed as indicated in solid outline in FIGS. 2 and 3. With the lift fork structure raised, the ram is disposed as indicated at 56A in dash-double-dot outline in FIG. 2.

The fluid lines, such as those indicated at 65 in FIG. 3, for connecting the cylinder in ram 56 with a source of pressure fluid, may extend conveniently through the hollow interiors of the tube members in frame 22.

Considering now in greater detail the means through which apparatus is suspended on the outer end of boom 12, and referring particularly to FIGS. 2 and 4, rotator 14, with one important exception, is conventional in construction. Thus, the rotator includes the usual stationary base plate 66, relatively rotatable rotor 68, and retainer ring 70 which holds the rotor and base plate together. Mounted on base plate 66 is a fluidoperated motor 72 that drives a pinion 74 in the rotator. Pinion 74-, in a conventional way, drivinglyengages teeth in rotor 68. The important difference herein in rotator 14, is that interposed between rotor 68, plate 66 and ring are rings 76 of a suitable high friction material, such as that used in various types of friction clutches. With fastening together of plate 66 and ring 70, through tightening nut and bolt assemblies such as assembly 78, rings 76 press against opposite sides of the rotor, and exert a continuous drag thereon with the rotor turning.

In the organization being described herein, this feature in the rotator tends to minimize any tendency of apparatus 10 to revolve about an upright axis, out of control of motor 72.

Joined to the top of plate 66 are brackets such as bracket 80, and these brackets are pivoted to the outer end of boom 12 through a pivot pin 82. Pin 82 accommodates rocking of the rotator about a substantially horizontal axis 83 which extends transversely of the longitudinal axis of boom 12.

Considering now the construction of pivot assembly 16, this includes a pair of cylindrical tubes 84, 86 joined together, as by welding, at a right angle to one another. Tube 84 is above tube 86. Pairs of flanges 88, are welded to the opposite ends of tubes 84, 86 respectively. Tube 84 and flanges 88 are received between a pair of brackets 92 which are joined to and extend downwardly from rotor 68 in rotator I4. Interposed between each flange 88 and bracket 92 is a washer, such as washer 94, made of substantially the same high friction material as is used in previously described rings 76. Extending through axially aligned bores in brackets 92, and through the hollow interior of tube 84, is a pivot pin 96. The outside diameter of pin 96 is somewhat less than the inside diameter of tube 84,

and filling the space between the pin and tube is an elongated hollow cylindrical sleeve 98, also formed of substantially the same high-friction material as previously mentioned. Pin 96 is held in place by means of a nut 100 screwed onto one of its ends, and a locking pin assembly 101 secured to its other end.

Tube 86. and flanges 90 are received between brackets 102 which are joined to the outer end of upper arm member 36 in frame 22. Interposed between each flange 90 and a bracket 102 is a washer 104 corresponding to previously-mentioned washers 94. Similarly, disposed within the interior of tube 86 is an elongated hollow cylindrical sleeve 106 corresponding to sleeve 98. A pivot pin 108 extends through the in terior of sleeve I06, and through axially aligned bores provided in brackets 102. Pin 108 is held in place by means of a nut l 10 and locking pin assembly 11 I which correspond to previously described nut 100 and assembly 101, respectively.

The outsides of pins 96, 108 fit snugly against the insides of sleeves 98, 106, respectively. Nuts 100, 110, which are suitably tightened, cause washers 94, 104 to bear against flanges 88, 90, respectively. As a consequence, pivot assembly 16, while accommodating rocking of apparatus 10 about two right-angularly disposed substantially horizontal axes 112, 114, tends to damp out any tendency of the apparatus to rock too freely.

Explaining now how apparatus may be employed, let us assume that it is desired to use it to pick up, transfer and deposit a stack of sheets, such as previously-mentioned stack 18. Let us assume further (what will probably always be the case) that the stack (as shown in FIG. 2) lies with the sheets in it horizontal, and with the stack supported, as on slats (not shown), several inches above the ground.

The lift fork structure. is first swung down to its lowered position. With the fork structure so lowered, and supporting no load, apparatus 10 hangs below boom 12 with its various parts oriented substantially as shown in FIG. 2. More specifically, the spine in frame 22 is substantially vertical, and the tines of forks 44 extend substantially horizontally away (to the right in FIG. 2) of the frame. It will be apparent that with the parts in apparatus 10 disposed in this manner, what might be thought of as a load support platform defined by forks 44 is offset (to the right in FIG. 2) from the center-of-gravity of the apparatus (which is substantially directly beneath the pivot axis provided by pin 108).

While there are many ways of maneuvering apparatus 10, preferably, through operation of rotator 14, the apparatus is turned to place the forks tines to positions facing laterally toward one side of boom 12. The boom is then swung toward the stack, with the boom lowered sufficiently to place the tines at the proper elevation to shift beneath the bottom sheet in the stack. With swinging of the boom, the frame and forks advance toward the stack, generally in the direction of arrow 116 in FIG. 2.

When the forks tines are fully shifted beneath the stack, as shown in FIG. 2, and with the boom still continuing to swing in the same direction, the operator contracts ram 56 to swing the fork structure toward its raised position. With such tilting of the forks, and because of the offset condition described above of the load support platform defined by the forks, the forks and frame, and the stack of sheets, rock clockwise in FIG. 2 about the pivot axis provided by pin 108. In particular, the frame, forks and load of sheets rock to positions such as those illustrated therefor in dash-dot outline at 22A, 44A and 18A, respectively, in FIG. 2. And, with such rocking, the forks and load of sheets lift automatically away from the ground. It will thus be apparent that with apparatus 10 manipulated in this manner while picking up a load, the actual picking up of the load is rather a simple operation as far as any steps required of the operator are concerned.

In most instances, the operator continues to contract ram 56 to place the fork structure in its raised position, thereby to place the stack of sheets on edge (on fork positions 44b) within cradle 40. On such occurring, apparatus l0 and the load of sheets rock back about the axis provided by pin 108, with the spine in frame 22 reassuming a substantially vertical disposition.

It will be noted that with frame 22 constructed as described, and with the fork structure in its raised position with the lines substantially paralleling the spine in the frame, apparatus 10 has a rather slender, upright side profile, with a width not very much greater than the thickness of a full stack of sheets. This is an important feature in the invention, since it is one which makes the apparatus particularly easy to maneuver into a relatively small or narrow opening, such as a window opening, in a building. In other words, with the parts in the apparatus folded-up, so-to-speak, there are no parts therein which jut out to one side or the other which make it difficult for the apparatus to be inserted through a window or other opening in a building. Referring for a moment to FIG. 1, it will be noted how the overall compactness of apparatus 10 enables it to be maneuvered to shift a stack of sheets through building opening 19 which, as can be seen, is not much wider than the on-edge width of the stack.

The operator, with the stack picked up and placed within the cradle, may then maneuver the boom in any suitable way to shift the stack to the desired location. When such a location is reached, the fork structure may be lowered to set the stack down with the sheets again horizontal. It will be obvious that if a relatively wide opening is available in a building for transferring in a stack, the fork structure in apparatus 10 need only be tilted up sufficiently to provide adequate clearance for the stack to be passed through the opening.

Friction rings 76 in the rotator inhibit any tendency of the apparatus while carrying a stack of sheets to revolve out of control of motor 72 (i.e., to overrun the motor). In the absence of such rings, such a situation could develop with high winds acting on the sheets, or because of inertial forces resulting with the sheets moving with swinging of the boom. Similarly, the friction sleeves and washers provided in pivot assembly 16 tend to damp out any excessive rocking of the apparatus. It is, of course, desirable that a certain amount of rocking be permitted to prevent overstressing of parts in the apparatus and boom.

The invention thus contemplates a novel apparatus for picking up, transporting and depositing a load of sheet-like articles. The apparatus proposed is characterized by simplicity, a high degree of maneuverability, and good compactness. Contributing to the latter feature is the novel construction of frame 22 which has the narrow side profile discussed above. With forks folded up, and closing off the open side of cradle 40 in the apparatus, there are no parts therein which jut out to inhibit maneuverability of the apparatus.

While a preferred embodiment of the invention has been described herein, it is appreciated that variations and modifications may be made without departing from the spirit of the invention.

It is claimed and desired to secure by Letters Patent:

1. Apparatus for handling a stack of building material sheets and the like comprising an elongated upright rigid frame,

means in said frame defining upper and lower subv stantially parallel and horizontal pivot axes therein adjacent the frames opposite ends, said lower pivot axis being positioned substantially directly below said upper pivot axis,

a generally L-shaped swingable lift fork structure pivoted for swinging relative to said frame about said lower pivot axis between a lowered position for picking up and depositing a load, and a raised position for transporting a load,

said lift fork structure having a pair of generally right-angularly disposed load-support parts, said parts, with the lift fork structure in its said lowered position, being disposed with one part generally horizontal and the other part generally vertical, and with the lift fork structure in its said raised opposite end pivoted to said lift fork structure for swinging the latter between said positions with exposition being disposed with said one part generally vertical and said other part generally horizontal, said one and other load-support parts, with said lift fork structure in its said raised position, along with said frame extending about a cradle zone in said apparatus for cradling a load, with said other loadsupport part then defining the base of said zone, to

tension and contraction of the power-operated means.

2. The apparatus of claim 1, wherein said frame includes an elongated upright spine, and with said lift fork structure in its said raised position, said one load support part is spaced from and substantially parallel to said spine, and said other load support part extends and between said one part and said spine adjacent the lower elongated extensible-contractible power-operated end ofthe latte" means having one end pivoted to said frame and its 

1. hApparatus for handling a stack of building material sheets and the like comprising an elongated upright rigid frame, means in said frame defining upper and lower substantially parallel and horizontal pivot axes therein adjacent the frame''s opposite ends, said lower pivot axis being positioned substantially directly below said upper pivot axis, a generally L-shaped swingable lift fork structure pivoted for swinging relative to said frame about said lower pivot axis between a lowered position for picking up and depositing a load, and a raised position for transporting a load, said lift fork structure having a pair of generally rightangularly disposed load-support parts, said parts, with the lift fork structure in its said lowered position, being disposed with one part generally horizontal and the other part generally vertical, and with the lift fork structure in its said raised position being disposed with said one part generally vertical and said other part generally horizontal, said one and other load-support parts, with said lift fork structure in its said raised position, along with said frame extending about a cradle zone in said apparatus for cradling a load, with said other load-support part then defining the base of said zone, and elongated extensible-contractible power-operated means having one end pivoted to said frame and its opposite end pivoted to said lift fork structure for swinging the latter between said positions with extension and contraction of the power-operated means.
 2. The apparatus of claim 1, wherein said frame includes an elongated upright spine, and with said lift fork structure in its said raised position, said one load support part is spaced from and substantially parallel to said spine, and said other load support part extends between said one part and said spine adjacent the lower end of the latter. 